Android 中的 HttpUrlConnection 设置范围被忽略

Question

我正在尝试使用 Android 从我的服务器获得 206 响应。

这是代码。

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_splash);
    new AsyncTask<Void, Void, Void>() {
        @Override
        protected Void doInBackground(Void... params) {
            try {
                URL url = new URL("http://aviddapp.com/10mb.file");
                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                urlConnection.setRequestProperty("Range", "bytes=1-2");
                urlConnection.connect();

                System.out.println("Response Code: " + urlConnection.getResponseCode());
                System.out.println("Content-Length: " + urlConnection.getContentLength());
                Map<String, List<String>> map = urlConnection.getHeaderFields();
                for (Map.Entry<String, List<String>> entry : map.entrySet()) {
                    System.out.println("Key : " + entry.getKey() +
                            " ,Value : " + entry.getValue());
                }
                InputStream inputStream = urlConnection.getInputStream();
                long size = 0;

                while(inputStream.read() != -1 )
                    size++;

                System.out.println("Downloaded Size: " + size);

            }catch(MalformedURLException mue) {
                mue.printStackTrace();
            }catch(IOException ioe) {
                ioe.printStackTrace();
            }
            return null;
        }
    }.execute();
}

这是输出：

I/System.out: Respnse Code: 200
I/System.out: Content-Length: -1
I/System.out: Key : null ,Value : [HTTP/1.1 200 OK]
I/System.out: Key : Accept-Ranges ,Value : [bytes]
I/System.out: Key : Cache-Control ,Value : [max-age=604800, public]
I/System.out: Key : Connection ,Value : [Keep-Alive]
I/System.out: Key : Date ,Value : [Tue, 04 Oct 2016 07:45:22 GMT]
I/System.out: Key : ETag ,Value : ["a00000-53e051f279680-gzip"]
I/System.out: Key : Expires ,Value : [Tue, 11 Oct 2016 07:45:22 GMT]
I/System.out: Key : Keep-Alive ,Value : [timeout=5, max=100]
I/System.out: Key : Last-Modified ,Value : [Tue, 04 Oct 2016 07:36:42 GMT]
I/System.out: Key : Server ,Value : [Apache/2.4.12 (Unix) OpenSSL/1.0.1e-fips mod_bwlimited/1.4]
I/System.out: Key : Transfer-Encoding ,Value : [chunked]
I/System.out: Key : Vary ,Value : [Accept-Encoding,User-Agent]
I/System.out: Key : X-Android-Received-Millis ,Value : [1475567127403]
I/System.out: Key : X-Android-Response-Source ,Value : [NETWORK 200]
I/System.out: Key : X-Android-Sent-Millis ,Value : [1475567127183]
I/System.out: Downloaded Size: 10485760

现在我做同样的事情是纯粹的java.

public static void main(String... args) {
    try {
        URL url = new URL("http://aviddapp.com/10mb.file");
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setRequestProperty("Range", "bytes=1-2");
        urlConnection.connect();

        System.out.println("Respnse Code: " + urlConnection.getResponseCode());
        System.out.println("Content-Length: " + urlConnection.getContentLength());
        Map<String, List<String>> map = urlConnection.getHeaderFields();
        for (Map.Entry<String, List<String>> entry : map.entrySet()) {
            System.out.println("Key : " + entry.getKey() +
                    " ,Value : " + entry.getValue());
        }
        InputStream inputStream = urlConnection.getInputStream();
        long size = 0;

        while(inputStream.read() != -1 )
            size++;

        System.out.println("Downloaded Size: " + size);

    }catch(MalformedURLException mue) {
        mue.printStackTrace();
    }catch(IOException ioe) {
        ioe.printStackTrace();
    }
}

这是输出

Respnse Code: 206
Content-Length: 2
Key : Keep-Alive ,Value : [timeout=5, max=100]
Key : null ,Value : [HTTP/1.1 206 Partial Content]
Key : Server ,Value : [Apache/2.4.12 (Unix) OpenSSL/1.0.1e-fips mod_bwlimited/1.4]
Key : Content-Range ,Value : [bytes 1-2/10485760]
Key : Connection ,Value : [Keep-Alive]
Key : Last-Modified ,Value : [Tue, 04 Oct 2016 07:36:42 GMT]
Key : Date ,Value : [Tue, 04 Oct 2016 07:42:17 GMT]
Key : Accept-Ranges ,Value : [bytes]
Key : Cache-Control ,Value : [max-age=604800, public]
Key : ETag ,Value : ["a00000-53e051f279680"]
Key : Vary ,Value : [Accept-Encoding,User-Agent]
Key : Expires ,Value : [Tue, 11 Oct 2016 07:42:17 GMT]
Key : Content-Length ,Value : [2]
Downloaded Size: 2

如您所见，我在这两种情况下都收到了不同的响应代码。似乎 Android 没有将 Range 传递给服务器？这里发生了什么？

PS：如果文件大小为 1mb，我将得到 206。

Answer 1

我比较确定错误不在 Android 代码中。

看起来服务器可能提供了虚假结果。

您可以检查 third party tool (such as Postman) 以确定 Web 服务正在传送的 headers。

我使用 Postman 的结果。如您所见，它正在交付 HTTP 200（而不是 206）。它也没有达到上限 Content-Length。如果服务器是您的，也许检查它是否配置正确。还要检查您与其他服务器的代码。

Answer 2

我不确定这是否与 Content-Length 默认被 android 实现清除有关。从源代码中查看下面的片段，它说它默认执行 gzip 压缩。

https://android.googlesource.com/platform/libcore/+/2e317a02b5a8f9b319488ab9311521e8b4f87a0a/luni/src/main/java/java/net/HttpURLConnection.java

By default, this implementation of HttpURLConnection requests that servers use gzip compression and it automatically decompresses the data for callers of getInputStream(). The Content-Encoding and Content-Length response headers are cleared in this case.

您可以尝试使用以下代码禁用默认缓存以检查是否有效吗？

urlConnection.setRequestProperty("Accept-Encoding", "identity");

PS: 抱歉格式错误。使用手机版SO.

Answer 3

你好，你能试试这段代码吗，看来我在这里 HTTP 206。

new Thread() {
            @Override
            public void run() {
                try {
                    URL url = new URL("http://aviddapp.com/10mb.file");
                    HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
//                    urlConnection.setRequestMethod("HEAD");
                    urlConnection.setRequestProperty("Accept-Encoding", "");

                    urlConnection.setRequestProperty("Range", "bytes=1-2");
                    urlConnection.connect();

                    System.out.println("Response Code: " + urlConnection.getResponseCode());
                    System.out.println("Content-Length: " + urlConnection.getContentLength());
                    Map<String, List<String>> map = urlConnection.getHeaderFields();
                    for (Map.Entry<String, List<String>> entry : map.entrySet()) {
                        System.out.println("Key : " + entry.getKey() +
                                " ,Value : " + entry.getValue());
                    }
                    InputStream inputStream = urlConnection.getInputStream();
                    long size = 0;

                    while (inputStream.read() != -1)
                        size++;

                    System.out.println("Downloaded Size: " + size);

                } catch (IOException ioe) {
                    ioe.printStackTrace();
                }
            }
        }.start();

你只需要在异步任务中添加它。

检查此结果评论 on/off 这一行。

urlConnection.setRequestProperty("Accept-Encoding", "");

Answer 4

你试过吗：

    urlConnection.setRequestProperty("Range", "bytes=1000-");

Android 中的 HttpUrlConnection 设置范围被忽略

HttpUrlConnection setting Range in Android is ignored

java

android

httpurlconnection